Mangroves
are woody, specialized types of trees of the
tropics that can live on the edge, where
rainforests meet oceans. Found on sheltered
coastlines and river deltas, they grow in brackish
wetlands between land and sea where other plants
can't grow. They protect the coastline and prevent
erosion by collecting sediment from the rivers and
streams and slowing down the flow of water. There
are about

39.3 million acres of mangrove forests in the warm
coastlines of tropical oceans all over the world. More than
10.5 million acres, or 27% of mangrove forests are found in
Southeast
Asia.

Mangrove trees look
as if they grow on stilts. The stilts are their specialized
aerial roots which hold the trunk and leaves above the water
line. Mangrove forests are affected by the rising and
falling of the ocean's tides. The aerial roots and tap roots
can filter out the salt in the brackish water they grow in.
Support roots grow directly into the mud to anchor the tree.
Other roots snake up and down with the upward loops rising
above the salt water level. Salt crystals taken up by the
roots are stored in the leaves. The mangrove rids itself of
the salt by shedding its leaves after a while.

It is believed that
the earliest species of mangroves came from the Southeast
Asian region. There are more mangrove species in this region
than anywhere else in the world. It is thought that seeds of
the mangrove moved westward to India, East Africa and
finally to Central and South America on ocean currents 23 to
66 million years ago. Mangroves of the Americas have similar
but fewer species than those in Africa and far less than
Southeast Asia. The specialized seeds of the mangroves are
tough and float, and can travel great distances in salt
water and take root far from its parent tree. The seeds
germinate and grow into seedlings right on the parent tree.
During this time they acquire the carbohydrates they need
later to grow on their own. The tree eventually drops its
seedlings, where they may take root in the mud below, or are
swept out by the tide.

One of the most
biologically diverse forests, mangrove forests are known as
the "rainforests by the sea". The forests are the breeding
grounds for fish, shrimp, prawns, crabs, shellfish and
snails. Mud skippers are found in mangrove forests. The
mudskipper has made adaptations so it can skim across the
mud during low tide when the ground is uncovered in many
places, traveling from puddle to puddle. Mangrove forests
are also nesting sites for many shore birds and home to crab
eating monkeys and proboscis
monkeys,
fishing cats, lizards, sea turtles, and many more animals.
For many species of fruit bats, like the dawn
bat,
mangrove blossoms and fruit make up a large part of their
diet.

Mangroves have a
very specialised adaptations that enable them to live in
salty waters. Breathing roots allow them to survive in
anaerobic sediments. Buttresses and above-ground roots
enable them to grow in unstable mud flats. Their foliage
removes excess salt from the sap, and they conserve water to
cope with periods of high salinity. Their seeds are bouyant
to allow them to disperse and establish themselves in new
areas.

Today mangrove
forests are one of the most threatened habitats in the
world. Mangrove roots are very susceptible to pollutants
like crude oil clogging their lenticels, and continual
flooding from artificial dikes and sea walls. Mangroves act
as sinks which concentrate pollutants like sewage, toxic
minerals and pesticides and herbicides. Over time the stress
of the pollutants and reduced light kill large areas of
mangroves forests. Mangrove wood also makes a superior kind
of charcoal and many trees are being cut down to sustain
local charcoal industries. Mangrove forests are also being
filled in for developments and as a form of mosquito
control.

Public awareness and
education about the mangrove forests may help protect them.
It is neccesary to involve local communities in managing and
protecting their mangroves. Designated conservation areas
may also save some of the forests. However, national
governments have not been able to enforce laws and regulate
development and industry to save the wetlands. Adequate
provisions for conservation and restoration have not been
included in development of the mangrove wetlands.